Fluid pressure pump or motor



Feb. 20, 1951 R. w. FERNSTRUM FLUID PRESSURE PUMP OR MOT OR Filed Dec. 4, 1947 a INVEgOR. 7 6*? MET/5 Ll/i 3Y I HTTYS Patented Feb. 20, 1951 FLUID PRESSURE PUMI? i932, ltTQTOR Robert W. Fernstrum, Detroit, Mich assignor to Marine Products Company, Detroit, Mich a corporation of Michigan Application December 4, 1947, Serial No. 789,681

Claims.

Thi invention relates to fluid pressure pumps o r motors, and, in particular, to such pumps or motors having resilient rotors.

One object of this invention is to provide a fluid pressure pump or motor having a rotor with resilient vanes which engage cam intake and outlet members arranged between cavities conimunicating with theintake and outlet ports respectively of the casing, these cam members being formed separately from the casing and subse quently attached thereto.

Another object is to provide a fluid pressure pump or motor with cam members of the above type having substantially fiat portions extend-- ing between the cavities and also having inclined ramps at opposite ends thereof extend inginto the cavities so that the flexing of the vanes and the consequent acceleration and deceleration are performed within the cavities themselves and not between the cavities.

; Another object is to provide a fluid pressure pumpor motor with cam members of the above type having flat portions of sufiicient length and with a rotor having resilient vanes spaced sufficiently close togetherthat when one vane is leavinga flat portion, the next succeeding vane has already entered the same flat portion of the cam member, thereby providing a complete seal between the intake and outlet cavities and ports and reducing the carryover of fluid, especially at high speeds.

Another object isto provide a fluid pressure size; of the left-hand end of the pump or motor shown ih Figure 1;

Figure 3 is a vertical cross-section taken along theline 33 in Figure 2 Figure 4 is an approximately horizontal sectiontakeri along the Zigzag line 4-5 in Figure 3, with the rotor in top plan view and showing the flexing of the vane thereof against the cam plates and also the fluid supply and discharge pockets; and v Figure 5 is a fragmentary side elevation of the left half of the pump or motor casing, similar to the upper portion of Figure 3, with the rotor removed; and showing one of the cam plates and the adjacent fluid supply and discharge pockets.

i5 for receiving machine screws It by which the two halves are secured together.

The casing half 52 is provided with a bore ll and the casing half it with an alignedbo re l8 fr: receiving a rotor shaft [9, the bore l8 being locatd within anaxially projecting boss 20. The end. of the bore i8 is closed by a closure plate 2| and lubricant is supplied to the left-hand end of the shaft is through bore 22 which is threaded to receive the threaded stem 23 of a lubricant cup or fitting 2 While a grease cup has been shown at 2%, it will be understood that any other type of conventional lubricating device may be employed, such as the well-known lubricant fittings used with a pressure lubricant gun. In order to prevent leakage around the midportion of the shaft is, the casing half I; is provided with a counterbore 25 equipped with a packing at which is compressed bythe tubular portion 2'? of a gland 28. Extending outward in opposite directions fromthe portion 21 (Fig ure 2) are integral arms 29 which are bored as at St to receive bolts 3]. The latter also pass through aligned bores 32 in corresponding inte-, gral arms 33 forming portions of an axially projecting boss St on the casing half l2 which contains the counterbo-re 25. By tightening the nuts 35 on the bolts 3|, the tubular portion 21 of the gland 23 is forced into the counterbore 25, compressing the packing 26 to the desired extent.

The outer right-hand end portion of the rotor shaft is is supported by a conventional antifriction bearing unit 33 which is mounted in a shouldered bore 31 within a bearing boss 38:- and held in position by a retaining ring 39 snapped into an annular groove ll] (Figure 1). The bearing boss 33 is supported upon an arm 4| extending axially outward from the central portion of the casing half l2 and having a machined flat portion 52 at the bottom thereof to facilitate mounting the pump or motor upon an engin or other machine support. A central flange or rib casing and increasing its rigidity. A collar 44 is secured by a set screw 5 to the shaft l9 adjacent the inner race of the anti-friction bearing unit 36 to prevent end motion of the shaft IS. A

The pump or motor to is provided" 3 driving pulley gear or sprocket (not shown) is mounted on the right-hand end of the shaft [9 on the opposite side of the anti-friction bearing unit 36 from the collar 44, completing the arrangement for preventing end motion of the shaft The casing half I2 is provided with a cover portion 46 (Figure 1) which has an inner surface or end wall 41 engaging the corresponding inner surface 48 of the casing half [3. The surface 48 extends around the edge of a cylindrical bore or rotor chamber 49 having an end wall 50. The lower portion of the chamber 49 is provided with a drainage port which is threaded to receive a plug 52. The casing half I3 is provided with an upwardly-extending top portion 53 having intake and discharge ports 54 and 55 respectively (Figure 2). These ports are preferably threaded to receive the threaded ends of intake and discharge pipes. The ports 54 and 55 open into radiallyextending pockets or cavities 56 and 51 respectively separated by a sector-shaped bridge portion 58 (Figure 5). Similarly, the cover portion 46 of the casing half 12 is provided with corresponding radially-extending pockets 59 and 88 (Figure 4) aligned respectively with the pockets or cavities 56 and 51 and similarly separated by a sectorshaped bridge portion 6!.

The bridge portions 58 and Bi are bored and threaded as at 62 and 63 to-receive set screws 64 by which a pair of oppositely-bent cam members 65 and 66 are secured to the bridge portions 58 and 6 I, the exposed surfaces 51 and 68 (Figure 4) being machined to receive the cam members 65 and'66. Each of the cam members 65 and 66 consists of a central portion 69 (Figures 4 and 5) having a fiat rotor-engaging surface 70 and outwardly-inclined ramp portions H and 12 which have inclined contact surfaces 13 and 14 respectively. The inclined portions 'H and 12 extend outwardly into the pockets or cavities 56, 51, 59 or 60, according to where the particular cam member 65 or 66 is located.

Keyed or otherwise drivingly secured as at 15 (Figure 1), to the shaft [9 is the hub is of a rotor,

generally designated 11. In addition to the hub 16, the rotor Tl consists of a disc I8 which is tightly secured to the hub 16 and which has molded upon and around it a vane unit 19 which is formed of elastic deformable material such as rubber or synthetic rubber. The disc 18 is provided at circumferentially-spaced intervals with holes 80 (Figure 3) through which the elastic deformable material extends so as to secure the vane unit 19 firmly to the disc 18 and hence to the hub 16.

The vane unit 19 is provided with a central rib 8| extending outward from the hub 16 and with its side walls parallel to the side walls of the disc 18. Integral with the rib 8| and positioned at intervals around it are sector-shaped blocks or projections82 (Figure 4) of approximately the same width as the separation of the flat surfaces 16 of the cam members 65 and 66. Extending from the opposite ends of the rotor 11 and integral with the trailing edges of the blocks or projections 82 are radially extending vanes 83 which are inclined obliquely to a plane perpendicular to the axis of rotation of the rotor shaft 19, hence are inclined obliquely to the rib 8 l. The vanes 83 on opposite sides of the rib 8| simultaneously engage the adjacent end walls 41 or 56' of the rotor chamber 49. The vanes 83 are flexed axially almost into contact with the side walls of the-rib 8| when they engage the flat contact surfaces of the cam members 65 and 66.

I 4 The vanes 83 along their lower edges are cut away as at 84 from the hub portion 85 of the vane unit 79 so as to permit the vanes 83 to flex freely.

By the foregoing construction, the cam members 65'and 66 may be accurately manufactured to precise dimensions by forming them in dies in an inexpensive and. rapid manner, after which they can be attached to the bridge portions 58 and 6! by the screws 64. The surfaces 61 and 68 against which they are seated are machined in the same operation with the machining of the end Walls 4'! and 5 of the casing halves l2 and I3. The pockets or cavities 56, 51, 59 and 60 are, of course, preferably formed during the casting operations of the casing'halves I2 and I3. The rotor 71 can be rotated in either directionmerely by removing it from the shaft I9 and reversing its position upon the shaft. I?

In the operation of the invention, the various parts of the pump or motor I8 are assembled as shown in the figures, and power is applied to the rotor shaft [9 to rotate the rotor 11. As the rotor" 11 rotates in the direction of the arrow (Figure' 3), it draws in fluid through the intake port 54 by way of the pockets or cavities 56 and 59, carries this fluid around the periphery of the bore or rotor chamber 49, and discharges it through the discharge port 55 by way of the pockets or cavi-- ties 51 and 68 (Figure 4). In each case, the fluid can pass freely between the pockets 56' and 59 or 51 and 68 by way of the upper outer corner portions 86 and 87 thereof (Figure 5) adjacentthe ports 54 and 55, the portions 86 and 81 serv-' ing as connecting passageways between the respective cavities or pockets.

As the vanes 83 approach the bridge portions 58 and 6|, they engage the ramps ll of the cam members 65 and 66 and are flexed into the positions shown in Figure 4, closely adjacent the rib a 8L, As shown in Figure 4, the blocks or projections 82 are spaced at such intervals around the periphery of the rotor 11, and the flat surfaces 16 are of such comparative widths that before one pair of vanes 83 leaves the flat surfaces. 10, another pair of vanes is already engaging'the sur faces 78, thus giving an overlapping effect to the vanes. Thus, an efiective seal is maintained and no acceleration or deceleration occurs after the vanes have left the pockets or cavities 51, 68 or entered the cavities 56 and 59. The rotor '11 is so constructed and proportioned that the vanes 83 fit snugly into the spaces 88 (Figure 4) between them and the leadingedges 89 of the blocks or projections 82, thereby reducing carryover of fluid to a minimum.

While the operation of the invention has been described as that of a pump, it will be understood that it may also be used as a motor, merely by feeding pressure fluid to the port 54 and allowing 1 it to discharge from the port 55. This will rotate the rotor Ti and rotor shaft [9, whereupon power A can be taken off the latter by means of a gear, sprocket, pulley or the like (not shown). Experience with the invention has proved that the device will operate as a pump at higherpressures and at higher speeds than has been possible with pumps of this type heretofore made. Ordinarily, when a pump of this type is operated at high speed, the pump begins to be starved for fluid as the speed is increased beyond a particular 1 speed, depending upon the design of the pump. The provision of the radially extending pockets 56, 51, 59 and 60, however, in the present inven-;

tion, admits fluid to the vanes 83 throughout their 7 entire lengths, down to the hub portion 85 of the anenit 1a. p he'pmvisicn of h locks 82'a1so lllsthe pace more complete y between successive.

sets, of vanes 83 and decreases the fluid carry over effect f om the p ke s. 5.1 and. 60 to the p c 5 and 59 past th cam memb rs 6 and What I claim is:

. 1, A-fl d s e p mp or motor comprisin a casing having therein a rotor chamber with spaced end walls and spaced fluid intake and dis-,

charge ports, said end walls having bridge por tions disposed between said ports, a rotor shaft rotatably mounted in said casing, a rotor mounted on said shaft and having radiallyextending vanes of elastic deformable material on the opposite sides of said rotor simultaneously engageable with saidend walls, and cam members mounted on said bridge, portions and projecting inwardly from said end walls, said vanes being disposed in flexing engagement with said cam members, said cam members having ramp portions inclined rela-r tively to said end walls and extending toward said bridgeportions and projecting inwardly from i end Wall ,v said vanes being disposed in flexn 'e sasem nt with said cam members, said cam members havin raml mortions inclined relatively QS id nd; walls and extending toward said ports,

said ,end walls havingfluid intake and discharge cavities therein extending alongside said vanes and communicating respectively with said intake and discharge ports.

3. A fluid pressure pump or motor comprising a casing having therein a rotor chamber with spaced end walls and spaced fluid intake and dis charge ports, said end walls having bridge portions disposed between said ports, a rotor shaft rotatably mounted in said casing, a rotor mounted on said shaft and having radiall extending vanes of elastic deformable material on the opposite sides of said rotor simultaneously engageable with said end walls, and cam members mounted on said bridge portions and projecting inwardly from said end walls, said vanes being disposed in flexing engagement with said cam members, said cam members having substantially flat central portions and ramp portions inclined relatively to said end walls and extending toward said ports, said end walls having fluid intake and discharge cavities therein extending alongside said vanes and communicating respectively with said intake and ing engagement with said cam members, said cam.

intake andv discharge. ports, sai ramp p ti s extending into said cavities.

. 5, A fluid pressure pump or motor, comprisingav casing having therein a rotorchamberrwith:

, spa d end walls and spaced fluid intake and,

discharge portssaid end walls having bridge nor-r tions disposed between said ports, a rotor shaft: rotatably mounted in said casing, a rotor mounted:

on said shaft. and having radially extendin vanes.

Qfxelastic deformable material on the opposite sides of said rotor simultaneously engageable with said; end walls, and cam members mounted on:v said bridge portions and projecting inwardly: from? said end walla-said vanes beingdisposed in flexing; engagementwith said cam members, said cam members having substantially flat central DUI: tiQnS and ramp ortions inclined relatively to said end wallsand extending toward said ports, said end walls having fluid intake and discharge cavie,

ties therein extending alongside, said vanes and! communicating respectively with said intake: and.

discharge ports, the ramp portions of theicam members on the opposite end walls of said casing; being inclined in opposite directions relativel to;

the, adjacent fiat central portions of said cammembers into the cavities adjoining said ramp, po t o s 6. A'fluid pressure pump or motor comprising;

a, casing having therein a rotor chamber with:

r spaced end. walls and spaced fluid intake and dis-V charge ports, said end walls having bridge; pore tions disposed between, said ports, a rotor Shaft rotatably mounted in said casing, a rotor mountedn. sai s ft and havin radially xtending vanes:

of elastic deformable material on the opposite sides of said rotor simultaneously engageable with said end walls, and cam members mounted on said bridge portions and projecting inwardly from said end walls, said vanes being disposed in flexing engagement with said cam members, said cam members having ramp portions inclined relatively to said end walls and extending toward said ports, said rotor having circumferentially-spaced axially extending projections around the periphery thereof and said vanes extending laterally from said projections, said vanes on opposite sides of said rotor flexing axially toward one another into the spaces between said projections upon engagement with said cam members.

'7. A fluid pressure pump or motor comprising a casing having therein a rotor chamber with spaced end walls and spaced fluid intake and discharge ports, said end walls having bridge portions disposed between said ports, a rotor shaft rotatably mounted in said casing, a rotor mounted on said shaft and having radially extending vanes of elastic deformable material on the opposite sides of said rotor simultaneously engageable with said end walls, and cam members mounted on said bridge portions and projecting inwardly from said end walls, said vanes being disposed in flexing engagement with said cam members, said cam members having ramp portions inclined relatively to said end walls and extending toward said ports, said rotor having circumferentiallyspaced axially extending projections around the periphery thereof and said vanes extending laterall from said projections obliquely to the axis of rotation of said rotor, said vanes on opposite sides of said rotor flexing axially toward one another into the spaces between said projections upon engagement with said cam membars.

8. A fluid pressure pump or motor comprising a casing having therein a rotor chamber with spaced end walls and spaced fluid intake and discharge ports, said end'walls having bridge portions disposed between said ports, a rotorshaft rotatably mounted in said casing, a rotor mounted on said shaft and having radially extending vanes of elastic deformable material on the opposite sides of said rotor simultaneously engageable with said end walls, and cam members mounted on said bridge portions and projecting inwardly from said end walls, said vanes being disposed in flexing engagement with said cam members, said cam members having ramp portions inclined relatively to said end walls and extending toward said ports;

said rotor having a peripheral rib with circumferentially-spaced axially extending projections around the periphery of said rotor and said vanes extending laterally from said projections, said vanes on opposite sides of said rib flexing axially toward one another into the spaces between said projections upon engagement with said cam members.

9. A fluid pressure pump or motor comprising a casing having therein a rotor chamber with spaced end walls and spaced fluid intake and discharge ports, said end walls having bridge 'portions disposed between said ports, a rotor shaft rotatably mounted in said casing, a rotor mounted on said shaft and having radially extending vanes of elastic deformable material on the opposite sides of said rotor simultaneously engageable with said end walls, and cam members mounted on said bridge portions and projecting inwardly from said end walls, said vanes being disposed in flexing engagement with said cam members, said cam members having ramp portions inclined relatively to said end walls and extending toward said ports, said rotor having circmnferentiallyspaced axially extending projections around the peripher thereof and said vanes being arranged in pairs of approximately V-shaped formation and extending laterally from said projections, said vanes on opposite sides of said rotor flexing axially toward one another into the spaces between said projections upon engagement with said cam members. 1

10.. A fluid pressure ump or motor comprising a casing having therein a rotor chamber with spaced fluid intake and discharge ports and a bridge portion therebetween, a rotor shaft rofit'a'tably mounted in said casing, a rotor mounted on said shaft and having radially extending vanes of elastic deformable material on the opposite sides thereof, and a cam member mounted on saidbridge portion and projecting inwardly in an axialdirection, said vanes being disposed in flexing engagement with said cam member, said cam member having a substantially flat central por tion and ramp portions at the opposite ends thereof inclined relatively to said flat central portion and extending toward said ports.

ROBERT W. FERNSTRUM.

I REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 7 Name Date 1 455,668 Latch July 7, 1891 801,891 Misner et al Oct. 1'7, 1905 1,372,586 Zerkle Mar. 22, 1921 2,189,356 Briggs Feb. 6, 1940 2,460,952 Simer et a1. Feb. 8, 1949 

